To study the effects of aging on a) the repair potentials of parodontal tissues subjected to a variety of surgical challenges which simulate those currently practiced in periodontal therapeutics, and b) to complete the long term studies initiated under grant DE03014. These include autoradiographic studies of amino acid, carbohydrate and ribonucleic acid turnover, in evaluation of aging parodontal tissues, as well as, electron microscopic studies of the age changes observed with the light microscope. As a result of the significant information derived from our initial investigations the short term studies proposed below are now feasible and we anticipate that they will furnish data of clinical relevance. 1. To evaluate autoradiographically a) the effect of surgical rewounding, and b) periosteal retention (split thickness) versus periosteal elevation (full thickness) flap surgery on the repair potentials of aging periodontal tissues, 2. To evaluate in aging animals the reformation of surgically injured periodontal fibers, and 3. To evaluate the repair potential of aging human gingival tissues following a standardized gingivectomy using ultrastructural methodology at the light and electron microscope levels. How age changes effect the cellular kinetics, behavior, growth, development and repair potentials of periodontal tissues, as well as, how age changes may contribute to periodontal disease in man remains the central purpose of these studies.